You don’t learn a good fiction-writing style by reading formal documents or newspapers. If you tend to officialese or journalese, you need to read more novels. A good fiction-writing style is concrete rather than abstract, direct rather than roundabout—and never opts for the safety of impersonal phrasings.
So far, so obvious. The only other advice I know is—keep it varied. Mix up short sentences with long sentences, vary the rhythms of your sentences, take different angles of attack. By ‘angles of attack’, I mean ways of feeding material through the structure of a sentence.
I don’t trust stylistic advice in the form of prohibitions. Two of the popular ones are: avoid passive verbs and avoid adverbs. Okay, you wouldn’t want to use too many of either. (Passives, for examples, are more roundabout rather than direct, and often impersonal.) But avoid altogether? That goes against the principle of variety.
I believe that acquiring a good fiction-writing style is about broadening one’s range or possibilities and learning more ways of saying things—not about cutting them down. Of course, it’s much easier to obey a prohibition and edit things out. Broadening one’s range is far more difficult, and there are no neat rules for it.
The prohibition approach to style seems mostly geared to crime fiction and action thrillers. In those genres, yes, a tight-lipped, pared-back sort of style is often what you want. But fantasy isn’t a rat-tat-tat sort of genre.
Side-note. Does Bill Gates bully you too? My Microsoft spelling-and-grammar check is always warning me against writing non-sentence fragments when I want to write non-sentence fragments. It also objects when I don’t put ‘and’ before the last item in a list—
Bells rang, buzzers buzzed, orders were shouted.
Likewise, when I use ‘then’ as a kind of conjunction—
He reared up on his knees, then collapsed forward again.
Not to mention the occasional passive sentences that it tries to re-order and make active.
Hah! I stand my ground. I think my spelling-and-grammar check wants to stop me writing fiction. But it won’t win. Never surrender!